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#Post#: 81--------------------------------------------------
State of the planet
DIR By: misplon
Date: November 19, 2012, 11:32 pm
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STATE OF THE PLANET
By Sir David Attenborough
The documentary starts off with an introduction by visiting the
island of Hawaii. Sir David uses Hawaii as an example of what is
happening to the planet.
Man only reached Hawaii 1700 years ago. Hawaii looks like a
paradise but there has been a great loss of species. In
environmentally Hawaii is tragically impoverished and this is
what is happening to the world. The mountain slopes of Hawaii
have been emptied of their biological riches. Hundreds of
species of animals and plants have disappeared since man has
come. Whenever humans have settled on an island great loss of
species occur. It is very important to know why this has
happened. We have named so far one and a half million species.
There could be as many as 100 million. The different type of
species is known as biodiversity. This document will explore the
five different factors that are contributing to the next
possible sixth extinction which may happen this century. We need
to have an idea of the amount of environmental change needed to
cause a mass extinction of life. The last mass extinction was 65
million years ago when most of the dinosaurs died. A ten mile
wide meteor travelling at 20 thousand miles an hour hit the
coast of South America. Over 50% of the planets species went
extinct. The impact that man has had on Earth is the same as a
modern meteor strike. If we want to see what man`s life was when
it started, it is back in Africa. Africa is the home of mankind.
If you want to see the mega fauna (large animals) only in
Africa.
50000 years ago there were big herds of mega fauna on every
continent. Around that time in a very short period those animals
started to go extinct, except Africa. 50000 years ago man
started to move away from Africa, the animals in other countries
were hunted to extinction. As man was evolving so was the
animals, so they became used to the fact that man was hunting
them. When they moved the other animals didn`t know them and
therefor they were hunted to extinction.
Humans are switching predators. It is a predator that eats many
types of things so if one goes extinct it just switches. The
hedgehog population on an island grew from 5-10 thousand.
Regeneration rate: how quickly a species is able to reproduce
itself. The first factor is:
Overharvesting
Humans use over efficient methods to gain resources and that led
to overharvesting our precious resources both on land and sea.
Today trees are being cut down 10 x faster than new ones can
grow. 70% of fish species are being removed above the
regeneration rate. Up to half of all plant growth a year is used
for man. Modern technology allows us to take too many fish out
of the sea. Each year up to half the harvest of plants is for
man only. Rare wild species are taken for luxury food. 30% of
the world`s resources have been used up in the last 30 years.
Introduction of alien species
Alien species are not natural animals or plants from that area.
This often tips the balance.Rabbits were introduced to
Australia, they were not use to the new place so they graze
everything and then they die of starvation because there was
nothing left. Hawaii had over 100 species of birds, but over
half are dead. They made the situation worse when they brought
more and more species. Our descendants will inherit an
impoverish world.
Destruction of habitat
The destruction of habitat is doing more damaged to biodiversity
than any other human activity. We take over land for use and
urbanization. The problem started when we start doing this at a
rapid pace. The Fynbos has more species than the Amazon. There
are over 5000 types of Fynbos that cannot be found anywhere else
in the world. 40% of the Fynbos land has been destroyed by
buildings and farming. If you take away the home of the species,
the species goes dead. 350 years ago explorers went to Charka
Canyon in New Mexico and found a settlement that was built by
the Indians 1000 years ago. They only lived there 300 years and
then abandoned it. 250000 wooden beams were used in the
buildings. Packrats use the same toilets for over 100 years and
then it fossilizes. They looked at the poo to see what they
were eating. When the Indians arrived there were a lot of trees,
then they went to the mountains to look for trees, but the
damage had already been done. The destruction of habitat is
doing more damage to biodiversity than any other human activity.
Is the human species deliberate destructive? Early man had to do
their best to control nature, but now we have technology so in a
way we have broken nature.
They dissolve the midden of the packrat in nitrogen. From their
results, 1000 years ago their pine forests in the Charka Canyon.
They were cut down and a draught came and the water table
dropped so the trees didn`t grow back the Indians couldn`t grow
crops. This is happening all over the world.
Islandisation
Islands that are undisturbed are amongst islands that are
modified. Islandisation cause loss of species because of change
of conditions and the area is not big enough. A road can cause
islandisation. The smaller the island the vulnerable the
species. Even nature reserves are a form of islandisation.
Danger of species living in isolation is that one by one they
all die.
Pollution
Pollution is generally a localized problem. Pollution of the
atmosphere is a problem that affects the whole world. Carbon
dioxide causes global warming and is a greenhouse gas. The more
carbon dioxide there is the warmer the earth becomes which
causes sea levels to rise. Global warming has happened before.
10000 years ago an area of sea use to be dry land. Global
warming causes changes of temperatures. Humans have accelerated
global warming and scientists are concerned whether nature can
cope.
Conclusion
Change is not a bad thing when it happens slowly. Our planet is
in dire condition today due to the fact that these 5 factors are
happening too fast. Mankind is making the sixth mass extinction.
With the education of people we can do amazing things.
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